1. Field of the Invention
This invention relates to the transmission of clock signal information as a part of the transmission signal from a transmission facility to a receiving facility and to the recovery of the clock signal at the receiving facility for use in processing the received signal and in particular to the transmission of the clock signal information and pulse signal information by amplitude modification of input pulse signals in accordance with clock signal information wherein the input pulse signals are of the non-return to zero type.
2. Prior Art
The use of pulse signals of the non-return to zero type for the transmission of information is well known. A non-return to zero pulse signal is one that has transitions which are coincident with clock signals. The various transmission systems using pulse signals require the clock signal used for various timing functions at the transmission facility to be present at a receiving facility to provide the proper time base needed for processing the received pulse signals. Various arrangements have been used to transmit clock signal information which is processed at the receiving facility to recover or regenerate the desired clock signal. Such prior arrangements include phase encoding techniques which require excessive bandwidth and frequency division modulation (FDM) arrangements which require a great deal of extra generation and demodulation circuitry. In addition, the problem of recovering clock information is magnified when high pulse rates are involved since phase distortion increases and the amount of shift in pulse transitions is significant with respect to the clock period.